(1) Field of Invention
This invention relates to a safety hook device that may be used in combination with an overhead transporting means, and the hook device is so adapted that the object to be hoisted and transported may be coupled and uncoupled automatically.
(2) Prior Art
In the transport of objects by overhead cranes or trolleys, it is often desirable that a safety hook be used in order to minimize danger to personnel, damage to the transported object, equipment or other material.
In the electrolytic production of aluminum, for example, large carbon anodes are used, and much of the transportation required in moving the anodes from station to station is by an overhead means. To produce an anode, the carbon is molded and baked into a block using a suitable binder. After baking, the anode block is assembled with a rigid metal bar extending vertically upward from the center of an upper portion of the block. The finished anodes are then transported to a smelting area where the anodes are inserted into an electrolytic cell containing a molten bath of aluminum salt. The rigid metal bar then functions as an electrical conductor and is suspended from a bus bar over the electrolytic cell.
Volume production of aluminum requires the use of large numbers of anodes since the anodes are consumed in the electrolytic process. It is desirable that a hook device be simple and quick to operate and also be provided with a safety feature to prevent involuntary disengagement. Handling and transporting the anodes are significant cost factors in producing aluminum, and speed in engaging, disengaging and transporting is important.
A prior hook device used for transporting anodes is comprised of a hoisting bar having a pin extending outward from a bottom portion of the bar, a slidable movable housing surrounding the bar and pin, and an attaching means on the end of the bar opposite the end having the outward extending pin for the purpose of attaching the hook device to the hoisting cable. To couple an anode bar, the housing is raised so as to be clear of the pin, the pin is inserted through an opening in the anode bar, and the housing is then dropped so as to surround the connection between the hook device and anode bar and thus prevent involuntary uncoupling. An adaptation of this device provides means for automatic raising of the housing and ejecting the pin at the point of desired uncoupling.
Other known safety hook devices include Cook U.S. Pat. No. 3,929,231 which discloses a hook device comprising a rectangular housing having a closed upper end, a movable pin mounted on a support structure attached to the outside of the housing and the pin coaxially aligned with a pair of holes through opposing walls of the housing so that the pin can be inserted through the housing and positive engagement between the pin and the housing obtained thereby. A pin actuating means activated by the crane operator is also provided so that the pin may be inserted and retracted through the holes of the housing walls. To couple an anode bar, the pin actuating means retracts the pin so as to permit entry of an upper portion of the anode bar. An opening through the anode bar is provided, the opening being coaxially aligned with the holes in the housing walls. After the anode bar is properly positioned in relation to the housing, the actuating means causes the pin to be inserted through a hole in the first housing wall, through the opening in the anode bar, and then through the hole in the second housing wall. Involuntary uncoupling is prevented by locking the pin in place through the use of the actuating means. A positive lock is provided by the Cook device, but pin alignment is critical for positive engagement, and since the housing surrounds the upper portion of the anode bar having an opening for the pin, it is not possible to determine visually that the hook device and anode bar are positively coupled.
Muddiman U.S. Pat. No. 2,357,054 relates to a hoisting hook for apertured articles such as plating anodes. The hook portion is formed from a round rod having an elongate vertical shank with an attaching means to a hoisting means on its upper end. The lower end of the rod is bent so as to provide an outward projecting portion that is inserted into an opening in an upper portion of the anode. A latching means attached to a tubular sleeve surrounding the vertical portion of the hook can be raised or lowered by sliding the freely movable sleeve on the vertical portion of the hook. When the latching means is lowered, a bottom portion engages an upper portion of the anode preventing the anode from disengagement with the hook. Since the sleeve does not lock in place, it can be accidentally moved and involuntary disengagement could occur.
Other safety hooks for hoisting devices of interest are disclosed in Grove U.S. Pat. No. 2,986,421, Hohler U.S. Pat. No. 2,537,829, and Elliott U.S. Pat. No. 3,239,266.
It is an object of this invention to provide a hook device that is quick and simple to couple or uncouple from an object to be hoisted.
It is also an object of this invention that the device be provided with a safety feature which will prevent involuntary uncoupling from an object to be hoisted.
It is a further object of this invention that the device may be coupled or uncoupled by an automatic means.
These and other objects and advantages of this invention will be apparent from an examination of the appended drawings and the following description .